Printing machines



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22%.; MM Imlent Charles H.5chweBe i56f i) J52, M W I vq+iorne s UnitedStates Patent 2,951,442 PRINTING MACHINES Charles H. Schwebel, Euclid,Ohio, assignor to Addressagraph-Multigraph Corporation, Cleveland, Ohio,a corporation of Delaware Filed Mar. 13, 1957, see. No. 645,798 '6Claims. (Cl.101149.5)

This invention relates to printing machines and to printing methods.More specifically, the invention relates to a method and apparatus fortransfer printing, by heat and pressure, from a master to a copy sheet.

In the printing arts, it is often desirable to print a number of imagesfrom a single master sheet or strip. For example, mailing strips or thelike including a plurality of individual addresses representative of amailing list are sometimes utilized for a series of diflerent mailingoperations. Preparation of a complete mailing strip for each mailingoperation is highly undesirable from an 2,951,442 Patented Sept. 6, 1960inc mailing operations without requiring preparation of a completely newmaster strip.

A principal object of the invention, therefore, is a new and improvedmethod of heat-and-pressure transfer print ing but which affords asubstantially greater number of usable copies than can be obtained withpreviously known processes of this kind.

A further important object of the invention is a new and improvedtransfer printing machine for imprinting a copy sheet with image datafrom a master strip by a heat-and-pressure transfer process whicheffectively prohad to a master mailing strip upon which the individualaddresses are formed as mirror or reverse images and from which theindividual addresses are duplicated or transferred onto copy sheetswhich may comprise either independent mailing strips or the material tobe mailed. Such transfer printing operations are commonly used in themailing of magazines, periodicals of various types, premium notices, andthe like. A printing machine of this kind is described and claimed inPatent No. 2,740,- 354 to John H. Gruver, issued April 3, 1956 on anapplication filed July 22, 1950; that particular machine utilizes amaster strip bearing image data which may be transferred to a copy sheetor copy sheets either by lithographic or hectographic techniques.

Another transfer printing machine suitable for addressing and similarapplications is described and claimed in a co-pending application ofJohn H. Gruver, Ser. No. 480,032, filed January 5, 1955; now Patent No.2,844,094, issued July 22, 1958, in the printing machine described inthat application, transfer printing is effected by positioning a copysheet at a printing station and pressing a master strip bearing an imageto be transferred against the copy sheet. In this instance, however,lithographic, hectographic, and similar duplication processes are notemployed; rather, the image on the master is transferred to the copysheet solely by the simultaneous action of heat and pressure. Themachine of the Gruver application utilizes a heated platen inconjunction with a master strip comprising a relatively thin porouscarrier bearing an image formed from thenno-softening ink.

For many applications, the heat-and-pressure transfer technique andapparatus described in the aforementioned Gruver application affordssubstantial advantages as compared with transfer printing arrangementsutilizing lithographic, hectographic or other more conventional imagetransfer procedures. For some applications, how ever, it is desirable toobtain a greater number of images or impressions from a single masterstrip than can be realized with the Gruver machine. In most instances,it is not possible to obtain more than five acceptable copies from themaster strip ina machine utilizing the heat and pressure technique setforth in the aforementioned application, whereas, particularly in thepreparation of mailing lists and the like, it may be desirable toutilize a single master address Strip, for as many as eight or ten longsthe useful life of the master strip and permits utilization of a singlestrip in printing a relatively large number of copies.

Another object of the invention is a method and apparatus forheat-and-pressure transfer printing which substantially increases thenumber of copies which may be realized from a single master imagewithout requiring a substantial increase in the cost of the printingequipment.

A corollary object of the invention is a method and apparatus forheat-and-pressure transfer printing which materially improves thequality of the printed image, particularly on prints made after themaster image has been utilized a number of times.

Another important object of the invention is a method and apparatus forincreasing the number of copies which may be obtained in aheat-and-pressure transfer printing process with a minimum ofmaintenance cost and without requiring the use of expensive operatingsupplies.

Other and further objects of the present invention will be apparent fromthe following description and claims and are illustrated in theaccompanying'drawings which, by way of illustration, show preferredembodiments of the present invention and the principles thereof and whatI now consider to be the best mode in which I have contemplated applyingthese principles. Other embodiments of the invention embodying the sameor equivalent principles may be used and structural changes may'be madeas desired by those skilled in the art without departing from thepresent invention and the purview of the appended claims.

In the drawings:

Fig. l is a front elevation view of the printing station and associatedelements of a transfer printing machine constructed in accordance withone embodiment of the present invention, a part of the machine havingbeen broken away;

Fig. 2 is a detail perspective view taken at the forward right-handcorner of the printing machine shown in Fig. 1;

Fig. 3 is a plan view of a portion of the printing machine of Figs. 1and 2 showing certain of the details thereof;

Fig. 4 is a sectional view taken along line 4-4 in' Fig. 3;

Fig. 5 is a front elevation view, similar to the righthand portion ofFig. l, of a printing machine constructed in accordance with anotherembodiment of the invention; Fig. 6 is a plan view of a part of theprinting machine of Fig. 5 taken along line 6-6 therein; s

Fig. 7 is an enlarged detail view showing a coupling device utilized inthe moistening apparatus of Fig. 6;

Fig. 8 shows the coupling device in an alternate position; and

Fig. 9 is a simplified schematic diagram of a control circuit for theapparatus of Fig. 6..

The transfer printing machineltl shown in Fig. 1 comprises a printinghead 11 which is utilized to suspend a claimed in the aforementionedGruver application; acoordingly, only a relatively brief description ofthe platen and anvil construction is included herein.

A pair of spacer blocks 14 and 15 are mounted upon the undersurface ofprinting head 11 and are utilized to support a horizontal mounting plate16 in fixed spaced relation to the printing head. Mounting plate 16, inturn, supports the platen 12, a pair of suspension springs 17 and 18being utilized for this purpose and being connected between the mountingplate 16 and a leveling plate 19 which forms a part of the platen. Theplaten 12 further includes a base plate 20 which is separated from theleveling plate 19 by an asbestos or other insulating pad 21; The baseplate 20 and pad '21 are mounted upon the leveling plate 19 by means ofa mounting bolt 22 which passes through a mounting block 23 afiixed toleveling plate 19 and is threaded into the base plate 20.

The printing station structure in the embodiment of Fig. 1 furtherincludes a pair of hollow bushings 25 and 26 which are anchored at theirlower ends to the leveling plate 19. A pair of fixed guide pins 27 and28 are disposed within bushings 25 and 26 respectively; the guide pinsare afiixed at their upper ends to the mounting plate 16 and thus serveto guide the platen 12 for vertical movement with respect to themounting plate 16. A vertical stop pin 30 is affixed to the mountingplate 16 and extends downwardly toward the platen 12 in a position toengage an adjustable stop member 31 which is afiixed :to theplaten 12.

' The printing station of printing machine 19 further includes means forguiding a master image strip 33 therethrough.' This master strip guidecomprises a frame 35 having a central opening 36 therein which conformsin dimensions to the individual image areas on the master strip 33.Frame 35 is mounted upon a pair of guide fingers 37 and 38 which in turnare supported from a pivotally mounted mounting block 40. A further pairof guide -fingers 41 and 42 are afiixed to the fingers 37 and 38respectively and are utilized in conjunction with fingers 37 and 38 toguide the movement of the master strip 33 through the printing station.Mounting block is yieldably connected to the platen 12 for verticalmovement therewith, the connection between these elements not beingshown in the drawings. The frame 35 is normally maintained in spacedrelation to the platen by means comprising an adjustable stop pin 45which is afiixed to and extends downwardly from an arm 46 being attachedto a portion of the printing machine frame. An angled spring plate 47 isattached to the pivotally movable mounting block 40 at one side thereofjust above the guide fingers 37 and 41. This angled plate 47 has one arm47A which engages the lower end of an adjustable screw 49 which extendsdownwardly from a plate 50 attached to the forward corner of the platenleveling plate 19.

.Printing machine 10 further includes a supply spindle 52 upon which thesupply reel 53 for the master strip 33 is mounted. From the supply reel53, the master strip is directed around an idler roller 54 and over asecond idler 55 to engage a diabolo roller 56, the diabolo roller beingsupported at the end of an arm 57 which is pivotal 1y mounted upon theframe of the printing machine as indicated at 58. From the diaboloroller 56, the master strip is directed around a feed spindle 60 andover a guide roller 61, through the aperture between fingers 37 and'41,across the opening 36 in the frame 35 of the printing station, and outthrough the slot between fingers 38 and 42. From the printing station,the master strip 33 extends over a guide roller 62 into engagement witha second feed spindle 63 and then into engagement with a second diaboloroller 64. From the diabolo roller 64, the master strip is directed overa further guide roller 65 to a rewinding or supply-reel 66. e

In order to Ieacha full understandiugof the operation of the transferprinting machine 10, it is necessary to consider the nature of themaster strip 33. The image master 33 comprises a relatively thin porouscarrier, usually a relatively inexpensive grade of paper. The addressesor other image data which are to be reproduced are imprinted upon thiscarrier with a thermo-softening ink; a preferred form ofthermo-softening ink suitable for heat-and-pressure transfer printing isdescribed in the co-pending application of John H. Gruver, Ser. No.480,070, filed January 5, 1955, now abandoned. The ink described in thatapplication comprises, in its preferred form, a mixture of gilsonite, awax selected from the group consisting of carnauba wax, parafiin, andbeeswax, and a non-drying liquid selected from the group consisting ofcastor oil, mineral oil, and oleic acid. An ink of this general typeafiords excellent impressions, for a limited number of copies, in a flatplaten machine of the kind described hereinabove when the platentemperature is of the order 015300 F.

Operation of the printing machine 10, as thus far described, isessentially similar to that of the printing apparatus described in theaforementioned Gruver application Ser. No. 480,032. Thus, a strip ofcopy sheets 70 which are to be imprinted with the image data from themaster strip 33 are advanced step-wise through the machine in thedirection indicated in Fig. 2 by the arrow A to locate the copy sheetssuccessively in printing position above the anvil or impression plate'13 and beneath the aperture 36 in the frame 35. At the same time, themaster strip 33 is advanced step-wise through the printing positionbeneath platen 20 and in registry with the aperture 36. The master stripfeeding arrangement is maintained in registry with the means utilizedfor feeding the copy through the printing station so that as each copysheet is positioned on the impression pad 13 the image carried by themaster 33 next subsequent to the last one printed is positioned over thenew copy sheet. A synchronized dual-feed arrangement suitable for use inthe printing machine 10 is described in detail in the aforementionedGruver Patent No. 2,740,354; inasmuch as the means selected for thisportion of the printing machine are not critical to the presentinvention, the driving arrangement has not been illustrated in thedrawings.

The platen base plate 20 is maintained at an elevated temperature,preferably by heating elements embedded in the base plate 20 thereof(not shown); a suitable thermostatic control arrangement may be providedfor the platen heaters. Each time a new address on the master strip 33is positioned over a new copy sheet in the strip 70, the printingmachine is actuated to impel platen 12 downwardly with respect to themounting plate 16; a suitable drive linkage is illustrated in theabove-noted Gruver application, Ser. No. 480,032.

As the platen20 starts its downward movement, the mounting block 40 ispivoted, moving the frame 35 and the portion of the master strip 33 inthe printing position toward the copy sheet 70 and impression plate 13.When the master sheet 33 engages the copy sheet 70, it can no longermove downwardly; the continued downward movement of the platen 12 bringsthe base plate 20' into engagement with the reverse or upper surface 71of the master strip and presses the master against the copy sheet. Atthe same time, heat from the heated platen base plate 20 softens the inkon the lower or obverse face 72 of the master strip and deposits 3.portion of the ink on the copy sheet, thereby transferring some of theink to the copy sheet. Subsequently, the platen 12 is returned to itsnormal or retracted position as illustrated in Figs. 1 and 2 and themaster strip 33 and copy sheet strip 70 are both advanced to bring asubsequent address into-registry with the next copy sheet. The processis then repeated to transfer the next address or other portion of imagedata to the subsequent copy sheet.

.In the transfer printingmcthod set-forth in the two above-identifiedGruver applications, heat and pressure alone are utilized to transferthe thermo-softening ink from the master strip 33 to the desired portionof the copy sheet strip 70. In the transfer printing method of thepresent invention, these factors are also of paramount importance in thetransfer of the image to the copy sheet. In accordance with the presentinvention, however, the reverse or uninked surface 71 of the masterstrip 33 is moistened before the transfer impression is made. For thispurpose, a liquid reservoir 75 is incorporated in the printing machine10, being mounted upon a bracket 76 aflixed to the frame of the machine.As best shown in Figs. 2-4, the liquid reservoir 75 has an outlet 77which connects the reservoir to a moistening pad 78 which is alsosupported from the bracket 76. Pad 78 may be fabricated from felt,sponge, or other suitable material capable of retaining and transferringliquid to the reverse surface 71 of the master strip without depositingundue quantities of liquid thereon and without leaking the liquid ontothe machine parts.

As indicated in the drawings, the pad 78 is aligned with the masterstrip 33 as the latter extends between guide roller 61 and the guideslot between fingers 37 and 41; as indicated in each of Figs. 1-4, thepad 78 is in contact with the reverse surface 71 of strip 33 wheneverthe master strip is under tension and is being moved through theprinting machine. Whenever movement of the master strip is arrested,however, the accompanying reduction in tension on the master strippermits the master strip to sag to the position indicated by the phantomoutlines 33A in Figs. 1, 2 and 4. Consequently, whenever the masterstrip 33 is not being pulled through the printing machine, it does notremain in contact with the moistening pad 78. This feature of themounting arrangement for the moistening device comprising reservoir 75and the moistening pad 78 is highly desirable in carrying out theinventive method, since otherwise the master strip might well becomesaturated with the moistening liquid or might at least become wet enoughthat it would tend to tear or break when tension was again appliedthereto to continue movement through the machine.

Any one of a number of different moistening agents may be employed incarrying out the inventive method, since it is not a hectographic orlithographic process and does not require that the moistening liquidreact in any manner with the thermo-softening ink comprising the imageto be transferred to and imprinted upon the strip of copy sheets 70. Theintrinsic effect of the moistening liquid, insofar as the master imageon the strip 33 is concerned, is not known; it is known, however, thatthe moistening of the reverse surface of the strip 33 permitsutilization of the master strip to produce a far greater number ofcopies than is possible in the dry heat-and-pressure arrangement setforth in the above identified Gruver applications. As of the presenttime, a number of different moistening agents have been tried and allhave given approximately equivalent performance. For example, water,ethyl alcohol, and carbon tetrachloride have all been tried with equalsuccess in conjunction with an image master using an ink of the kinddescribed in the aforementioned Gruver application, Ser. No. 480,070.-These highly diverse moisten- .ing agents make it possible to utilizethe master strip to obtain approximately twice as many impressions asthe same master strip affords when utilized in a dry heatand-pressuretransfer process. It is thus apparent that no chemical action as such isinvolved.

Moreover, it is by no means necessary or even desirable that the liquidemployed be a solvent for the ink on the master strip. Indeed, the veryreverse appears to be true, since the preferred thermo-softening ink isinsoluble in water, alcohol, and carbon tetrachloride. It is possiblethat the liquid, when subjected to the heat utilized as the moisteningagent.

from the heated platen 12 and vaporized thereby, fund tions as anemulsifying agent for the thermo-softening ink, although this is by nomeans certain. Another possible theory is that the moistening agent,once having been .volatilized, performs some catalytic action in aidingthe softening of the ink, although this is perhaps questionable in viewof the diverse nature of the liquids which have been found tobe-efficacious in carrying out the inventive method. In any event, theeffect achieved is similar to one of catalysis in that neither the inknor the moistening liquid is apparently changed in chemical form to anyextent in the printing process. Indeed, the improved results achievedwith the method of the invention may be purely mechanical in nature; thesteam or other vapor, in penetrating the pores of the paper stripnormally used as a carrier for the thermo-softening ink, may in effectsimply add to the total pressure applied to the ink and thereby enablethe reproduction of usable images with a strip which has otherwise lostits useful ness.

From an economic standpoint, the method of the invention presents thegreatest advantage when water is This is easily understandable in viewof the price difierential between water and virtually any other liquidwhich might be employed for this purpose. Moreover, it is equallyimportant to note that the inventive method may be carried outcompletely by a conventional heat-and-pressure transfer printer withonly the addition of the extremely simple and inexpensive moisteningdevice comprising reservoir 75, bracket 76, and moistening pad 78.

Figs. 5-9 illustrate another embodiment of the invention which in manyrespects is essentially similar to the printing machine 10 describedhereinabove in connection with Figs. 14. Thus, the portion of theprinting machine illustrated in Fig. 5 includes a printing head 11 whichis utilized to support a vertically movable heated platen 12 at theprinting station of the machine. and printing head structure may beessentially similar to that described in connection with Fig. 1 and mayinclude the mounting plate 16 suspended from the printing head 11 asindicated at 14, the platen 12 being vertically movably supportedbeneath the mounting plate. As before, the platen may comprise a heatedbase member 20 suspended from the leveling plate 19 and separatedtherefrom by the insulating layer 21. The same mounting arrangementcomprising the mounting block 23 may be utilized in this embodiment,along with the vertical guide 26 and the return spring 18.

The feeding system for the master strip 33 may be essentially similar tothat shown in the first-described embodiment; the web 33 is guided overthe rollers 54 and 55 and over the diabolo roller 56 into engagementwith the feed spindle 60; the diabolo roller 56, as before, may besupported upon a support member 57 pivotally mounted on the frame of themachine as indicated at 58. As it leaves the feed spindle 60, the masterstrip 33 is guided between the guide fingers 37 and 41 into the printingstation of the machine. The remaining unillustrated portion of theprinting machine 100 may be essentially similar to the correspondingportion of the printing machine 10 shown in Fig. 1.

Printing machine 100, however, includes a moistening device 101 which isin some respects substantially different from that of the previouslydescribed embodiment. The moistening device 101, as. shown in Figs. 5and 6, comprises a support bracket 102 which is affixecl to the frameofthe printing machine and which extends upwardly therefrom to a locationadjacent the portion of the master strip 33 intermediate roller 55 anddiabolo roller 56. liquid reservoir 104 is mounted at the upper end ofthe bracket 102 and is provided with an outlet 105 which connects thereservoir to a moistening pad 106; the reservoir 104, outlet 105 andmoistening pad 106 maybe essentially similar in-construction to thereservoir 75,

The platen outlet 77, and moistening pad 78 of the first-describedembodiment.

. In this instance, however, the moistening pad 106 is not supported ina fixed position with respect to the master strip 33. Rather, pad 106 ismounted upon a support member 107 which is pivotally supported upon atransverse extension 108 of the bracket 102. This mounting arrangement,which is best shown in Fig. 6, permits movement of the support member107 and the moistening pad 106 between the operative position shown insolid lines in Fig. 6 and the inactive position indicated by the dashoutlines 106A-and 167A therein.

The transverse extension 108 of bracket 102 is also utilized to supporta solenoid 110 and a coupling device 111; the coupling device isutilized to connect the solenoid tothe upper portion 112 ofthe-moistening pad support member 1137. The coupling device'111, whichis shown in detail in Figs. 6-8, includes a U-shaped bracket 113 whichis afiixed to the transverse portion 108 of the principal mountingbracket 102. A double notched cam 115 is included in the coupling device111 and is joumaled upon a post 114 afiixed to the bracket 113. Thecoupling device further includes a-transverse coupling link 116 whichextends across the bracket 113 through suitable apertures in the endportions or legs of the bracket. Coupling link 116 is connected at oneend to the upper extension 112 of the moistening pad support member 107and the other end of the coupling link is suitably connected to theshaft or plunger of the solenoid 110. This arrangement is best shown inFigs. 7 and 8. The coupling link 116 further includes a pair ofdownwardly extending dogs 118 and 119; as indicated in Figs. 7 and 8,dog 118 extends substantially parallel to the axis of movement 129 ofthe coupling device, whereas dog 119 is oriented at an acute angle withrespect to the axis 120. Figs. 7 and 8 also illustrate the configurationof the cam 115, which is provided with a pair of notches 123 and 124 atthe opposite ends thereof.

When the solenoid 110 is energized, the plunger 117 is driven in thedirection indicated in Fig. 7 by the arrow A against the biasing forceprovided by a spring 125. This movement of the solenoid plunger drivesthe coupling link 116 in the same direction and brings the dog 119 intoengagement with one surface 127 of the cam 115, rotating the camcounterclockwise through a minor arc to the position illustrated in Fig.8. When the solenoid 110 is subsequently de-energized, the plunger 117and connecting link 116 move in the direction opposite arrow A inresponse to the biasing force erected by the spring 125. Upon thisreturn movement, the dog 113 engages a second surface 128 of the cam 115and arrests the movement of the coupling link 116 in the positionillustrated in Fig. 8. In this position, with the coupling link 116extending farther to the left from bracket 113 (as seen in Figs. 68)than its original location, the moistening pad support member 167 isestablished in its operating or actuated position in contact with theuninked or reverse surface of the master strip 33.

The coupling device 111 and the moistening pad 166 remain in theactuated or operative position shown in Figs. 6 and 8 until the solenoid111 is energized a second time. When this is done, the solenoid againdrives the plunger 117 and the coupling link 116 in the direction ofarrow A. The dog 119 engages another surfiace 130 of the cam 115 androtates the cam to a position approximately perpendicular to the centerline 120 of the coupling device. Subsequently, when solenoid 110 isdeenergized and the plunger 117 and coupling link 116 begin their returnmovement in the direction opposite arrow A, the dog 118 engages thesurface 131 of cam 115 and returns it to the position shown'inFig. 7,except that the cam 115 has now been rotated through an arc of 180.Thus, the'coupling device 111 establishes. a predeterminedactuationsequence for the movement ofrnois- T tening pad 106 between itsoperative or actuated position and its normal or unactuated position,the latter being indicated by the dash outline 106A in Fig. 6.

Fig. 9 illustrates, in an extremely simplified form, a control circuitfor the solenoid 110. In this figure, the solenoid operating coil isillustrated by the inductance A, one end of which is connected to oneterminal of a power supply. The other end of the coil 110A is returnedto the power supply through a pair of switches 135 and 1 36 which areconnected in parallel with each other. Switch 135 is mechanically orelectrically coupled to the starting switch of the printing machine,whereas switch 136 is suitably coupled to the stop switch of theprinting machine.

In operation, the printing machine 190 shown in Figs. 59 is in mostrespects similar to the previously described embodiment. At the outset,it may be assumed that the coupling device 111 is in its unactuated ornormal position as shown in Fig. 7 and maintains the moistening device1196 in its inactive position as indicated in Fig. 6 by the dash outline106A. Thus, when the starting switch of the printing machine is closed,switch 135 (see Fig. 9) is also closed and energizes the operating coil110A of solenoid 111). Energization of the solenoid actuates thecoupling device 111 to its second or actuated position as shown in Fig.8 and consequent- 1y pivots the support member 197 to bring themoistening pad 106 into contact with the uninked or reverse surface ofthe master strip 33. When the operator of the printing machine releasesthe starting switch, the coil 110A is de-energized, since switch 135returns to its normal or open position. As indicated hereinabove,however, the coupling device 111 does not return to its initial positionas shown in Fig. 7 but remains in the actuated position of Fig. 8 sothat the master strip 33 is continuously moistened as it moves throughthe printing machine.

Subsequently, whenever the operator finds it necessary or desirable tostop the operation of the printing machine, the stop switch of themachine is actuated and, consequently, the switch 136 is closed, againenergizing solenoid coil 116A. This second energization of the solenoidand subsequent opening of switch 136 when the stop switch of the machineis released returns the coupling mechanism 111 to its initial position(see Fig. 7) and, accordingly, returns the moistening pad 106 to itsinitial position 1116A out of contact with the master strip 3 3.

It is thus apparent that the printing machine shown in Figs. 5 9efiectively carries out the inventive transfer printing method bymoistcning the reverse surface of the master 33 before thethermo-softening inkimage on the master is transferred to a copy sheet.As in the previously described embodiment of the invention, it

i is preferred that the moistening liquid utilized be water in view ofthe obvious economic advantages thereof. The printing machine 1% furtheravoids excess moistening of the master strip by maintaining themoistening device out of contact with the master strip whenever the.machine is shut down. Moreover, this objective is accomplished withoutrequiring continuous energization of any electrical operating devicesuch as the solenoid 110, which is enengized only at the times that themachine is started and stopped.

it will be obvious to those skilled in the art that the apparatusembodiments of Figs. 1-4 and of Figs. 5 -9 represent only two of manypossible -means for carrying out the inventive method, although theyafford substantial advantages as compared with other apparatusarrangements. Moreover, the method itself may be accomplished completelyand effectively by hand in a relatively low-speed transfer printingprocedure. Whether carried out by hand or by either of the two preferredapparatus embodiments of the invention illustrated .and described hereinby any other suitable means, the

transfer printing method of the invention affords substantially greaternumbers of copies, in a transfer printing process using athermo-softening ink and heat-andpressure transfer, than can be obtainedwith previously known techniques. Consequently, the useful life of themaster strip or other master image member is considerably prolonged. Theapparatus embodiments of the invention are quite inexpensive withrespect to the additional equipment required for the printing machines;both of the apparatus embodiments afiord substantial advantages in thatthey effectively minimize maintenance cost. In this respect theapparatus embodiment of Figs. 1-4 is preferable in that it entailsutilization of somewhat simpler equipment that the positively-actuatedarrangement of Figs. 5-9, although the latter may be preferable in someapplications.

Hence, while I have illustrated and described the preferred embodimentsof my invention, it is to be understood that these are capable ofvariation and modification, and I therefore do not Wish to be limited tothe precise details set forth, but desire to avail myself of suchchanges and alterations as fall within the purview of the followingclaims.

I claim:

1. A transfer printing method for imprinting a copy sheet with imagedata from a master comprising a relatively thin porous carrier having athermo-softening ink image deposited on a given surface thereof, saidtransfer printing method comprising the following steps: moistening thereverse surface of the master; bringing the master and the copy sheetinto pressure contact with each other, the image-bearing surface of themaster being in contact with the image-receiving surface of the copysheet; and heating the moistened master while in pressure contact withthe copy sheet to soften the ink and deposit a portion thereof upon thecopy sheet.

2. A transfer prin' g method for imprinting a copy sheet with image datafrom a master comprising a relatively thin porous carrier having athermo-softening ink image deposited on a given surface thereof, saidtransfer printing method comprising the following steps: moistening thereverse surface of the master with a volatilizable liquid in which theink is insoluble; bringing the master and the copy sheet into pressurecontact with each other, the image-bearing surface of the master beingin contact with the image-receiving surface of the copy sheet; andheating the moistened master while in pressure contact with the copysheet to volatilize the moistening liquid and to soften the ink, therebydepositing a portion of the ink upon the copy sheet.

3. A transfer printing method for imprinting a copy sheet with imagedata from a master comprising a relatively thin porous carrier having athermo-softening water-insoluble ink image deposited on a given surfacethereof, said transfer printing method comprising the following steps:moistening the reverse surface of the master with water; bringing themaster and the copy sheet into pressure contact with each other, theimagebearing surface of the master being in contact with the 10image-receiving surface of the copy sheet; and heating the moistenedmaster while in pressure contact with the copy sheet to vaporize theWater and to soften the ink, thereby depositing a portion of the inkupon the copy sheet.

4. A transfer printing method for imprinting each of a plurality of copysheets with image data from a single master comprising a relatively thinporous carrier having a thermo-softening ink image deposited on a givensurface thereof, said transfer printing method comprising the followingsteps: moistening the reverse surface of the master; bringing the masterand the individual copy sheets successively into pressure contact witheach other, the imagebearing surface of the master in each instancebeing in contact with the image-receiving surface of the copy sheet; andheating the moistened master, while in pressure contact with each copysheet, to soften the ink and deposit a portion thereof upon each copysheet.

5. A transfer printing method for imprinting each of a plurality of copysheets with image data from a single master comprising a relatively thinporous carrier having a thermo-softening ink image deposited on a givensurface thereof, said transfer printing method comprising the followingsteps: moistening the reverse surface of the master; bringing the masterand one copy sheet into pressure contact with each other, theimagebearing surface of the master being in contact with theimage-receiving surface of the copy sheet; heating the moistened masterwhile in pressure contact with the copy sheet to soften the ink anddeposit a portion thereof upon the copy sheet; and repeating the recitedsteps with each copy sheet to imprint the image thereon.

6. A transfer printing method for imprinting each of a plurality of copysheets with image data from a single master comprising a relatively thinporous carrier having a thermo-softening ink image deposited on a givensurface thereof, said transfer printing method comprising the followingsteps: moistening the reverse surface of the master; bringing the masterand one copy sheet into pressure contact with each other, theimage-bearing surface of the master being in contact with theimage-receiving surface of the copy sheet; heating the moistened masterwhile in pressure contact with the copy sheet to soften the ink anddeposit a portion thereof upon the copy sheet; and repeating only thelast two steps with succeeding copy sheets to imprint the image thereon.

References Cited in the file of this patent UNITED STATES PATENTS1,049,741 Lichtenstein Jan. 7, 1913 1,281,781 Jean Oct. 15, 19182,057,696 Sherman Oct. 20, 1936 2,068,268 Francis Ian. 19, 19372,398,288 Collins Apr. 9, 1946 2,501,495 Carroll et a1 Mar. 21, 19502,503,185 Wright Apr. 4, 1950 2,740,354 Gruver Apr. 3, 1956

